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Neurodiversity and Intelligence: Evaluating the Flynn Effect in Children with Autism Spectrum Disorder
Kenzie B Billeiter1, John Mark Froiland2, Justin P Allen3
1Department of Educational Psychology, Baylor University, Waco, TX, USA. Kenzie_Billeiter1@baylor.edu.
Child Psychiatry and Human Development
|May 3, 2021
Summary
Intelligence scores in children with autism spectrum disorder (ASD) are declining, not rising as seen in the general population. This study found a significant reverse Flynn Effect in ASD, impacting research and practice.
Area of Science:
- Psychology
- Neurodevelopmental Disorders
- Cognitive Science
Background:
- The Flynn Effect (FE) traditionally shows a rise in IQ scores by approximately 3 points per decade in general populations.
- Autism spectrum disorder (ASD) is a neurodevelopmental condition affecting social communication and characterized by restricted interests and repetitive behaviors.
Purpose of the Study:
- To investigate the presence and direction of the Flynn Effect in child and adolescent populations with autism spectrum disorder (ASD).
- To analyze changes in general intelligence scores over time within cohorts of individuals with ASD.
Main Methods:
- Utilized nine years of data from the National Database for Autism Research (NDAR).
- Analyzed intelligence scores from 671 individuals with ASD across nine cohorts.
- Employed linear regression to assess trends in IQ scores over time.
Main Results:
- A significant downward trend in general intelligence scores was observed in the ASD cohorts.
- A reverse Flynn Effect of approximately 5.4 IQ points per decade was identified.
- Mean IQ scores decreased from 92.74 in the first three years to 87.34 in the last three years of the study period.
Conclusions:
- The findings indicate a reverse Flynn Effect in individuals with ASD, contrasting with the general population.
- This trend has significant implications for educational, clinical, and legal considerations for individuals with ASD.
- Further research is needed to understand the underlying causes and long-term consequences of this observed decline.
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